Our proposed research will focus on new approaches to broad-spectrum therapy for antibiotic-resistant pathogens, using as our primary model organisms methicillin-resistant S. aureus (MRSA) and P. aeruginosa (PA). We have provided proof-of-principle that phagocytic cell activity can be activated in vitro and in vivo through transcriptional regulator HIF-1 and that HIF-1 is critically dependent on NF-kB signaling. He we are taking a broader view based on our published data applying mouse genetic tools and infectious disease model systems that identified and validate additional receptor signaling, signal transduction and transcriptional control pathways in phagocytic cells that are amenable to pharmacological manipulation to boost antibacterial capacities of macrophages and neutrophils. In Nature 2005, we found that mice lacking the IKKa kinase regulating NF-kB activation had increased inflammatory responses and bactercidal activity. In Aim 1, we will use in vivo and ex vivo studies the role of IKKa kinase in regulation of phagocyte bactericidal and inflammatory responses to MRSA and PA, and probe its relationship to HIF-1 mediated cellular energy metabolism. In Nature Immunology 2010, we discovered that mice lacking IKKP kinase regulating NFkB activation increased IL-ip/IL-1R signaling to boost neutrophil numbers and bacterial defense vs. GAS. In Aim 2 of the proposal, we will use ex vivo and in vivo models along with specific pharmacologic antagonists to evaluate the roles of IKKp kinase and downstream IL-ip/IL-1R signaling in regulation of phagocyte bactericidal and inflammatory responses to antibiotic-resistant bacterial pathogens. In Science 2006, we observed a role of A3 adenosine receptors in neutrophil chemotaxis, and in Aim 3 of the proposal we will study the role ofthe A3 receptor signaling in regulation of phagocyte bactericidal and inflammatory responses to MRSA and PA. In Immunity 2011, we found that P2X7 receptors mediate ATP detection and macrophage-mediated host defense against B. anthracis, and in Aim 4 we will probe the role of the ATP/P2X7 receptor signaling and inflammasome activation in regulation of phagocyte bactericidal and inflammatory responses